Stereoscopic microscope with means for varying stereoscopic viewing angle

ABSTRACT

A stereoscopic microscope comprises an object lens, a pair of stereoscopic observation optical systems arranged behind the object lens and light beam deflection means arranged between the stereoscopic observation optical systems and the object lens for varying a stereoscopic view angle.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a stereoscopic microscope widely usedin a medical field, which can vary a stereoscopic view field for anobject or an illumination angle for the object.

2. Description of the Prior Art

The stereoscopic microscope has been widely used in a medical field suchas operation or inspection, a research field and an industrial field andit is useful to enhance precision and safety in the operation.

A degree of a stereoscopic image in the stereoscopic microscope isdetermined by observing the object with a given base line spacingbetween a pair of left and right observation optical systems arrangedabove the object. As the base line spacing increases, the stereoscopiceffect increases. When a portion of the object to be observed is at adeep position, for example, in a narrow recess, illumination light doesnot reach it or it cannot be observed with the predeterminedstereoscopic view angle. Depending on the position of the portion to beobserved, it cannot be observed unless the illumination angle or thestereoscopic view angle is changed. Accordingly, in order to obtain aprecise stereoscopic image, it is desired to change the illuminationangle or the stereoscopic view angle during the observation.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a stereoscopicmicroscope which can vary a stereoscopic view angle and an illuminationangle to enhance an observation capability of a portion in a recess.

It is another object of the present invention to provide a stereoscopicmicroscope which can continuously vary a stereoscopic view angle with asimple construction.

It is another object of the present invention which can in parallel varythe degree of stereoscopic images of a main observer and a sub-observer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an optical arrangement of a first embodiment of a variablestereoscopic microscope of the present invention,

FIG. 2 is a front view of a four-plane reflection prism,

FIG. 3 shows an optical arrangement with the four-plane reflection prismbeing rotated by 90 degrees from the position shown in FIG. 1,

FIG. 4 illustrates a light beam axis on the four-plane reflection prism,

FIG. 5 shows an optical arrangement of a main portion of a secondembodiment,

FIG. 6 shows arrangement of a triangle prism and a deflection mirror,

FIG. 7 shows an optical arrangement with light beam deflection meansbeing rotated by 90 degrees from a position shown in FIG. 5,

FIG. 8 is a front view of an eight-plane reflection prism,

FIG. 9 shows an optical arrangement of a third embodiment,

FIG. 10 illustrates a function of a parallel planar prism which isreplaceable with a parallel planar mirror,

FIG. 11 shows an optical arrangement of an embodiment in which degreesof stereoscopic images by a main observer and a sub-observer can beparallelly varied,

FIG. 12 is a front view taken along a line I--I of FIG. 11,

FIG. 13 is a front view similar to FIG. 12, of other embodiment,

FIG. 14 shows an arrangement of an optical system of an embodiment forvarying an illumination angle;

FIG. 15 shows an arrangment as viewed in a direction II--II of FIG. 14,

FIG. 16 shows an arrangment of an optical system of other embodiment forvarying the illumination angle, and

FIG. 17 shows an arrangement viewed in a direction III--III of FIG. 16.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a main portion of a variable stereoscopic microscope of thepresent invention. It comprises a pair of stereoscopic observationoptical systems which uses a common object lens 1, a four-planereflection prism 2 having four reflection planes 2a, 2b, 2c and 2d asshown in FIG. 2 is arranged behind the object lens 1. A light from anobject point 0 passes through the object lens 1 and a componentreflected by the reflection plane 2a of the four-plane reflection prism2 is directed to a zoom lens 4a through a mirror 3a and then directed toan eye lens optical system Ea. A light reflected by the reflection plane2b of the fourplane reflection prism 2 is directed to a zoom lens 4bthrough a mirror 3b and than directed to an eye lens optical system Eb.

The reflection planes of the four-plane reflection prism 2 are inclinedby 45 degrees relative to a rear plane B but apexes of the horizontaland vertical planes are at different levels from the rear plane b.Namely, the apex of the horizontally opposing reflection planes 2a and2b is at P1 while the apex of the vertical reflection planes 2c and 2dis at P2. The four-plane reflection prism 2 is rotatably supportedaround an optical axis C of the object lens 1.

FIG. 3 shows an arrangement with the four-plane reflection prism 2 beingrotated by 90 degrees from the position of FIG. 1. The light from theobject point 0 passes through the object lens 1, is reflected by thereflection planes 2c and 2d of the four-plane reflection prism 2, andthe reflected lights pass through mirrors 3a and 3b and zoom lenses 4aand 4b, and are directed to the eye lens optical systems Ea and Eb,respectively.

FIG. 4 shows light beam axes on the four-plane reflection prism 2, La,Lb, Lc and Ld denote light beam axes on the reflection planes 2a, 2b, 2cand 2d, respectively, a base line spacing between Lc and Ld is muchlarger than a base line spacing between La and Lb. Thus, by rotating thefour-plane reflection prism 2, the base line spacing between the lightbeam axes on the reflection prism 2 can be changed so that thestereoscopic angle is changed.

FIG. 5 shows another embodiment of the present invention. It does notuse the four-plane reflection prism 2 but it exchanges reflectorscorresponding to the mirrors 3a and 3b shown in FIGS. 1 and 3. In placeof the four-plane prism 2, a triangular prism 5 having two left andright reflection planes 5a and 5b is used. A pair of left and rightdeflection mirrors 6a and 6b are arranged in reflection directions andanother pair of deflection mirrors 6c and 6d are arranged in a directionnormal to a line connecting the deflection mirros 6a and 6b.

The deflection mirrors 6a-6d are rotatably supported around the opticalaxis C of the object lens which passes through a crosspoint of the lineconnecting the pair of deflection mirrors 6a and 6b and the lineconnecting the pair of deflection mirrors 6c and 6d. When the deflectionmirrors 6a-6d are rotated by 90 degrees as shown in FIG. 7, the lineconnecting the deflection mirrors 6a and 6d is slightly shifted in thedirection of the optical axis C of the object lens, as seen from thecomparison of the line connecting the deflection mirrors 6a and 6d shownin FIG. 5. In FIG. 7, the reflection light from the triangle prism 5 isdirected to the deflection mirror 6c and 6d. Accordingly, the light pathis changed and the base line spacing is changed so that the degree ofstereoscopic image is changed.

In place of the four-plane reflection prism 2 shown in FIG. 1, aneight-plane reflection prism 7 shown in FIG. 8 may be used. Theeight-plane reflection prism 7 has four steps by combinations of thereflection planes 7a and 7e, 7b and 7f, 7c and 7g, and 7d and 7h. Byrotating it, four different stereoscopic images are obtained. Amulti-plane prism having any number of combinations of two planes, maybe used. Any combination of the deflection mirrors 6a-6d shown in FIG. 5may be used.

FIG. 9 shows a third embodiment of the present invention. An object 0 isstereoscopically observed by an inspector through a common object lens11 arranged in front of the object 0, two sets of mirrors 12a and 3a andmirrors 12b and 13b arranged parallelly behind the object lens 11, zoomvariable magnification optical systems 14a and 14b arranged on opticalaxes Oa and Ob, and observation optical systems 15a and 15b. The twosets of mirrors 12a and 13a, and 12b and 13b are continuously rotatablearound rotation axes Pa and Pb toward positions 12a' and 13a', and 12b'and 13b' shown by broken lines while keeping the parallel relationship.

A light beam emanated from the object 0 is converted to an afocal lightbeam by the object lens 11, and left and right split light beams arereflected by the mirrors 12a and 12b as shown by solid lines, thenreflected by the mirrors 13a and 13b to the optical axes Oa and Ob, andpass through the zoom variable magnification optical systems 14a and 14band the observation optical systems 15a and 15b.

The mirrors 12a and 13a are moved to positions 12a' and 13a', and themirrors 12b and 13b are moved to positions 12b' and 13b' which aresymmetric to the mirrors 12a and 13b with respect to the center axis ofthe object lens 11. Under this condition, the light beam emanated fromthe object 0 passes through the object lens 11, the mirrors 12a and 13alocated at the positions 12a' and 13a', the zoom variable magnificationoptical system 14a and the observation optical system 15a, and theobject lens 11, the mirrors 12b and 13b located at the positions 12b'and 13b', the zoom variable magnification optical system 14b and theobservation optical system 15b, and are directed to eyes of theinspector. Thus, the stereoscopic angle to the object 0 is variable.

By rotating the parallel planar mirror to change the base line spacingof the light beam impinged to the two optical systems from the objectlens 11, the degree of the stereoscopic image can be changed.

The combination of mirrors may be replaced by parallel planar prisms 16aand 16b having reflection planes as shown in FIG. 10 and the prisms 16aand 16b may be rotated around rotation axes Qa and Qb.

FIG. 11 shows an embodiment which allows parallel change of degrees ofstereoscopic views of a main observer and a sub-observer. FIG. 12 showsan arrangement as viewed from a line I--I of FIG. 11. A light from anobject point 0 passes through a common object lens 21 and is reflectedby four reflection planes PG,10 22a-22d of a four-plane reflection prism22. The reflected light beams pass through mirrors 23a-23d and zoomlenses 24a-24d and are directed to eye lenses in directions A-D. Thelight beam reflected by the reflection plane 22a passes through themirror 23a and the zoom lens 24a and is directed to the eye lens in thedirection A, and the light beam reflected by the reflection plane 22dwhich opposes to the reflection plane 22a passes through the mirror 23dand the zoom lens 24d and is directed to the eye lens in the directionD. A first stereoscopic image is formed by those two light beams.Similarly, a second stereoscopic image is formed by two light beamswhich are reflected by two other opposing reflection planes 22b and 22cand directed to the eye lens in the directions B and C.

The square reflection prism 22 is moved to change the stereoscopic view.In FIG. 11, when the square reflection prism 22 is moved from a solidline position P1 to a broken line position P2, the light beam whichcomes in the direction A is reflected by the reflection plane 22a and alight beam a1 is moved to a position a2. The light beam coming in thedirection D is reflected by the reflection plane 22d and a light beam d1is moved to a position d2. Thus, a spacing between centers of lightbeams a1 and d1, that is, a base line spacing changes so that thedirection of the first stereoscopic image is changed. Similarly, thedirection of the second stereoscopic image formed by the light beams inthe directions B and C is also changed. Referring to FIG. 12, the firststereoscopic image formed by the light beams a1 and d1 changes to a2 andd2, and the second stereoscopic image formed by the light beams b1 andc1 changes to b2 and c2.

FIG. 13 shows another embodiment. In the present embodiment, the fourreflection planes 22a-22d of the square reflection prism 22 shown inFIG. 11 are replaced by four separate mirrors 25a-25d. Other arrangementis similar to that of FIG. 11. The like numerals to those shown in FIG.11 designate the like elements.

In the present embodiment, a first stereoscopic image is formed by thelight beam a1 which is formed by the zoom lens 24a, mirror 23a andmirror 25a, and the light beam d1 which is formed by the zoom lens 24d,mirror 23d and mirror 25d. A second stereoscopic image is formed by thelight beam b1 which is formed by the zoom lens 24b, mirror 23b andmirror 25b, and the light beam c1 which is formed by the zoom lens 24cmirror 23c and mirror 25c. If those four light beams a1, b1, c1 and d1are at equal distance from the center axis Q of the object lens 1, thedegrees of the two stereoscopic views are equal.

When the light flux axis defined by the zoom lens 24b, mirror 23b andmirror 25b, and the light beam axis defined by the zoom lens 24c, mirror23c and mirror 25c are rotated around the center axis Q of the objectlens 21 in a direction of an arrow, the zoom lens 24b and 24c themirrors 23b and 23c and the mirrors 25b and 25c are rotated to brokenline positions and the light beams b1 and c1 are also rotated topositions b3 and c3. By simultaneously moving the mirrors 25a-25d alongthe center axis Q, the degree of the stereoscopic view is varied asshown in FIG. 11. In the present embodiment, an angle made by the viewdirection by the main observer and the view direction by thesub-observer can be set to other than right angle. Thus, the position ofthe sub-observer may be changed relative to the position of the mainobserver.

In the present embodiment, the square reflection prism 22 or the mirrors25a-25d are moved in order to vary the degree of stereoscopic view.Alternatively, the mirrors 23a-23d may be relatively moved in the samedirection, or the mirrors 25a-25d may be radially moved from the centeraxis 0 of the object lens 21.

FIG. 14 shows an arrangement of an optical system in an embodiment inwhich an illumination angle is varied, and FIG. 15 shows an arrangementof the embodiment viewed in a direction II--II of FIG. 14. An object 0is stereoscopically observed by an inspector through a common objectlens arranged in front of the object 0, an observation prism 32 arrangedbehind the object lens 31 and having two reflection planes 32a and 32b,mirrors 33a and 33b arranged on optical axis Oa and Ob, and finderoptical systems Fa and Fb including beam splitters and eye pieces.

An illumination optical system comprises a light source 35, a condenserlens 36 arranged on an optical axis Oc of the light source 35, a mirror37 for deflecting a light path, a relay lens 38 and a movable prism 39arranged behind the object lens 31. The movable prism 39 has a sidesectional shape which fits to a v-shaped groove 32c formed on a side ofthe observation prism 32 and has a reflection plane 39c for deflectingthe light from the relay lens 38 to the object lens 31, and it isslidable along the observation prism 32 in parallel to the center axisof the object lens 1.

The light emanated from the light source 35 passes through the condenserlens 36, is reflected by the mirror 37, passes through the relay lens38, is reflected by the reflection plane 39c of the movable prism 39,passes through the object lens 31 and illuminates the object 0obliquely. The light beam emanated from the object 0 is deflected by theobject lens 31 and split into two light beams by the reflection planes32a and 32b of the observation optical system prism 32. The split lightbeams are reflected at La and Lb of the mirrors 33a and 33b, passthrough the zoom lens systems 34a and 34b and are directed to the finderoptical systems Fa and Fb so that they are stereoscopically observed.

When the illumination system movable prism 39 is moved upward along thecenter axis of the object lens 31 as shown by a broken line, thereflection position of the illumination light beam is moved from Lc toLc' so that the illumination is done from a position closer to thecenter axis than the position before the movement. By continuouslymoving the illumination system movable prism 39 along the center axis ofthe object lens 31, the illumination angle to the object 0 can becontinuously changed. Similarly, by continuously moving the observationsystem prism 32 along the center axis of the object lens 31, thestereoscopic view angle can be continuously varied.

FIG. 16 shows an arrangement of an optical system of an embodiment inwhich the illumination angle and the stereoscopic view angle aresimultaneously varied, and FIG. 17 shows an arrangement of the opticalsystem as viewed in a direction III--III of FIG. 16. The like numeralsto those shown in FIGS. 14 and 15 designate the like elements. In thepresent embodiment, one movable prism 40 is shared by the observationsystem prism and the illumination system movable prism. The reflectionplanes 40a and 40b are used by the observation system prism and thereflection plane 40c is used by the illumination system movable prism.The movable prism 40 is movable along the center axis of the object lens41.

In FIG. 16, when the movable prism 40 is moved from the solid lineposition to the broken line position, the reflection position of theillumination light beam is moved from Lc on the reflection plane 40cshown in FIG. 17 to Lc', and the reflection positions of the observationlight beams are moved from La and Lb on the reflection planes 40a and40b to La' and Lb' so that the illumination light flux and theobservation light flux approach to the center axis of the object lens 1with the same bare line spacing. That is, the stereoscopic view angleand the illumination angle are changed at the same angle rate.

When the illumination angle and the stereoscopic view angle are to bechanged at the same rate depending on the application of thestereoscopic microscope, the embodiment of FIG. 16 is preferable to theembodiment of FIG. 14. However, the embodiment of FIG. 14 has a widerapplication because the illumination system movable prism 39 and theobservation system prism 32 can be moved either parallelly or singly.

In the above embodiment, the observation system prism is moved as asingle unit. Alternatively, the observation system prism may be dividedinto a plurality of sections. The direction of movement of the prism isnot limited to the direction of the center axis of the object lens butthe prism may be radially moved from the optical axis of the objectlens. By moving the prism away from the center axis, the base linespacing to the center axis is increased so that the base line spacingcan be adjusted as can be done in the previous embodiment in which theprism is moved along the center axis of the object lens.

In addition to the prism, the mirrors 33a, 33b and 37 or 43a, 43b and 47may be moved in union or independently in the direction of the centeraxis of the object lens or in the radial direction normal to the centeraxis. For example, in FIG. 14, if the illumination system movable prism39 is fixed and the mirror 37 is moved upward along the center axis ofthe object lens 31, the base line spacing to the center axis of theobject lens 31 is widened. When the movable prism 39 and the mirror 37are simultaneously moved in the opposite directions, for example, themirror 37 is moved upward and the movable prism 9 is moved downward, thebase line spacing can be more effectively widened.

What I claimed is:
 1. A stereoscopic micrscope comprising:an objectlens; a pair of stereoscopic observsation optical systems arrangedbehind the object lens to be used for obsrvation through the objectlens; and light beam deflection means arranged in a light path betweenthe stereoscopic observation optical systems and the object lens forvarying a stereoscopic angle, wherein said light beam deflection meansis a rotating polygon reflector rotatable around an optical axis of saidobject lens and having a reflective surface stepped in the direction ofthe optical axis of said object lens.
 2. A stereoscopic microscopecomprising:an object lens; a pair of stereoscopic observation opticalsystems arranged behind the object lens to be used for observationthrough the object lens; and light beam deflection means arranged in alight path between the steroscopic observation optical systems and theobject lens for varying a stereoscopic angle, wherein said light beamdeflection means includes a plurlaity of sets of deflection mirrorsarranged at different positions along the direction of the optical axisof said object lens which mirrors are rotatable in unison around theoptical axis of said object lens.
 3. A stereoscopic microscopecomprising:an object lens; a pair of stereoscopic observation opticalsystems arranged behind the object lens for observation through theobject lens at a stereoscopic angle; and light beam deflection meansarranged in a light path between the stereoscopic observation opticalsystems and the object lens for varying the stereoscopic angle of saidpair of stereoscopic observation optical systems, said light beamdeflection means including two sets of parallel reflection surfaces,wherein each set can positionally swing in symmetry with the other setabout the optical axis of said object lens.
 4. A stereoscopic microscopeaccording to claim 3, wherein each of said two sets of parallelreflection surfaces are opposed faces of a rhombic prism.
 5. Astereoscopic microscope comprising:an object lens; a pair of firststereoscopic observation optical systems arranged behind the object lensfor observation through the object lens at a stereoscopic angle; a pairof second stereoscopic observation optical systems, whose optical axesare arranged in a plane crossing a plane containing the optical axes ofsaid pair of first stereoscopic observation optical systems, forobservation through the object lens at a stereoscopic angle; and lightbeam deflection means having two pairs of deflecting surfaces for therespective stereoscopic observation optical systems, arranged in a lightpath between the stereoscopic observation optical systems and the objectlens, for simultaneously varying the stereoscopic angle of each of thetwo pairs of stereoscopic observation optical systems.
 6. A stereoscopicmicroscope according to claim 5, wherein the planes containing theoptical axes of said first and second stereoscopic observation opticalsystems intersect at an angle that can be varied and said pairs ofdeflecting surfaces can be relatively rotated to each other around theoptical axis of said object lens.
 7. A stereoscopic microscopecomprising:an object lens; a pair of first stereoscopic observationoptical systems arranged behind the object lens for observation of anobject through the object lens at a stereoscopic view angle; a pair ofsecond stereoscopic observation optical systems, whose optical axes arearranged in a plane crossing a plane containing the optical axes of saidpair of first stereoscopic observation optical systems, for observationof the object through the object lens at a stereoscopic view angle; andlight beam deflection means, arranged in a light path between thestereoscopic observation optical system and the object lens, for varyingstereoscopic view angles, said light beam deflection means including aset of four mirrors and a reflector having four reflection planes facingsaid mirrors, said set of mirrors and the reflector being movablerelative to each other in the direction of the optical axis of saidobject lens so as to vary simultaneously the stereoscopic view angles ofsaid first and second stereoscopic observation optical systems, whilemaintaining the same image sizes of the object observed therethrough. 8.A stereoscopic microscope comprising:an object lens; a pair of firststereoscopic observation optical systems arranged behind the object lensfor observation of an object through the object lens at a stereoscopicview angle; a pair of second stereoscopic observation optical systems,whose optical axes are arranged in a plane crossing a plane containingthe optical axes of said pair of first stereoscopic observation opticalsystems, for observation of the object through the object lens at astereoscopic view angle; and light beam deflection means, arranged in alight path between the stereoscopic observation optical system and theobject lens, for varying simultaneously the stereoscopic view angles ofsaid first and second stereoscopic observation optical systems whilemaintaining the same image sizes of the object observed therethrough,wherein the planes containing the optical axes of said first and secondstereoscopic observation optical systems intersect at an angle that canbe varied.
 9. A stereoscopic microscope comprising:an object lens; apair of stereoscopic observation optical systems arranged behind theobject lens for observation of an object through the object lens at astereoscopic angle; an illuminating system, located on the same side ofthe object lens as said optical systems, for illuminating the object atan angle; and light beam deflection means, having at least threedeflecting means, said light beam deflection means arranged in a lightpath between the stereoscopic observation optical systems and the objectlens, and also arranged in a light path between said illuminating systemand said object lens, for varying at least the angle of illumination ofthe object, by moving a first of said deflecting surfaces.
 10. Astereoscopic microscope according to claim 9, wherein said light beamdeflection means further varies the stereoscopic angle by moving asecond and a third of said deflecting means.
 11. A sterescopicmicroscope according to claim 10, wherein said light beam deflectionmeans simultaneously varies both the illumination angle and thestereoscopic angle.
 12. A stereoscopic microscope according to claim 11wherein said light beam deflection means is one prism block, and saidprism block is moved along the optical axis of said object lens.